For improving indoor air quality ("IAQ") in habitable working and living spaces and the like, the air is exhausted from the space to the atmosphere (or to another space) and is replaced by outside air which must be heated or cooled in order for the desired temperature within the space to be maintained. Equipment for improvement Indoor Air Quality is known in the art. It includes ventilation systems consuming a substantial amount of energy for heating or cooling the incoming air. Also, the advanced more efficient and energy conserving counter-flow heat exchangers were developed to transfer some heat to or from the air supplied to the space by heat exchange with the air removed therefrom.
For instance, U.S. Pat. No. 4,295,342 discloses a system wherein a heat exchange is effected in a simple and economical manner by allowing natural flow of a heat exchange fluid (such as a conventional refrigerant liquid) between two heat exchangers which are exposed to air at different temperatures. The two heat exchangers, which may conveniently take the form of fin-tube heat exchangers, are arranged with one end at a higher elevation than the other. As the refrigerant liquid absorbs heat and evaporates in the heat exchanger exposed to the warmer air, the vapor travels through the upper connecting line to the other heat exchanger, where it rejects heat and is condensed, the liquid flows through the lower connecting line back to the first heat exchanger, and so on, with heat exchange between the two air streams or masses occurring during the natural, continuous flow of the refrigerant in gaseous and liquid form.
U.S. Pat. Nos. 4,688,399, 4,771,824 and 4,896,716 also disclosed heat pipe heat exchangers with increased efficiency of transferring the heat from a heat source to a heat sink.
Disadvantageously, heat-pipe heat exchangers suffer from certain problems:
a length limitation, wherein the capacity of the heat pipe does not increase when the length of the heat pipe is extended beyond a certain maximum. PA1 in a heat pipe, a liquid and a vapor are moving in opposite directions, each impeding the flow of the other. PA1 when a heat pipe utilizes wicking to return liquid phase condensate to the warm end, a definite limit is placed on the length over which the wick can be effective. PA1 leakage causing cross-contamination through intermixing of the fluid streams.
It, therefore, would be highly desirable to have a heat transferring system overcoming the disadvantages of the prior art.